Ingredients:

For the sauce:

• 100 g bacon
• 2½ kg beef tenderloin
• 1 kg carrots, peeled and diced
• 500 g celery, cleaned and diced
• 500 g parsley root, cleaned and diced
• 1 kg onions, finely chopped
• 1 large lemon, sliced
• 175 g lard
• 125 g of full-fat mustard
• 200 ml of vinegar
• 2-3 litres of beef broth
• 750 ml cream (31%) at room temperature
• 5 juniper berries
• 10 peppercorns
• 10 allspice berries
• 10 bay leaves
• 200 g of granulated sugar
• 1 teaspoon of dried thyme
• salt and freshly ground pepper

For the roux:

• 100 g butter
• 100 g plain flour

To serve:

• Karlovy Vary dumplings
• cranberry sauce and whipped cream

Method:

1. Cut the bacon into 10cm sticks, roughly as thick as your little finger. Spread them on a tray and freeze for an hour – the bacon will harden, making it easier to skewer into the meat.
2. Pierce the meat with the prepared bacon. Season thoroughly with salt and pepper. Melt the lard in a large heavy-walled pot and fry the meat in it over a high heat until golden brown on all sides. Remove the meat from the pot, lower the heat and add the chopped root vegetables. As soon as they start to darken around the edges, add the onion. Sauté together until golden, then stir in the mustard and vinegar and cook for 5 minutes, stirring occasionally. Make sure the vinegar boils before adding any further ingredients - this makes sure it will give the base a pleasant sour taste and lose any unwanted pungency.
3. Pour the beef broth over the sautéed vegetables so that they are submerged (reserve about ⅓ of the broth for later, to finish the sauce), pour 250 ml of cream into the pot and add the spices, wrapped in linen. Sprinkle in the sugar, and add salt to taste. Then add the thyme, lemon and meat. Cover the pot with a lid and slowly simmer the beef until tender (around 2-3 hours, checking continuously).
4. Meanwhile, prepare the roux to thicken the sauce. Melt the butter in a saucepan, cover it with flour and stir until light brown. Leave to cool.
5. Transfer the softened meat to a spare saucepan and cover, so that it does not cool down. Remove the spices from the pot and blend the vegetable base until smooth. Pour in the rest of the stock, bring to the boil and thicken with the cooled roux, stirring vigorously with a whisk to dissolve. Boil for a few minutes, then pour in the remaining cream and heat it up to the so-called “first bubble” (don’t let it boil, as the cream will curdle).
6. Set aside the sauce and gently season it with salt, sugar, or a little vinegar. Slice the meat and serve immediately covered with sauce, alongside Karlovy Vary dumplings and garnished with cranberries and whipped cream.